Nanoscale electrical performance of multifunctional carbon fiber reinforced panels

The objective of this work is the investigation of the electrical current map by Tunneling Atomic Force Microscopy (TUNA) of carbon fiber-reinforced panels (CFRPs) impregnated with a multifunctional epoxy formulation. In particular, the formulation has been suitably designed to improve the flame resistance properties and contrast the electrical insulating properties of the epoxy resin. TUNA investigation was performed on the panels before and after the etching procedure for a more effective comprehension of the morphological features of the panels. The multifunctional panels were manufactured by an appropriately modified resin film infusion (RFI) process. TUNA acquisitions were carried out to evaluate the validity of the implemented infusion process. The effects of the different ply numbers (7, 14 and 24) on the TUNA electrical performance were assessed (see Figure 1). In particular, TUNA technique, which is able to detect ultra-low currents ranging from 80 fA to 120 pA [1-3], allowed the identification of the conductive paths which are represented by carbon nanotubes that are tightly attached to the carbon fibers with the typical tendency to accumulate in the areas through which the passage of the resin happens due to the specific infusion process. In this work, for all the manufactured panels, TUNA current images highlight the presence, between the layers of carbon fibers, of conductive three-dimensional networks of MWCNTs that take part successfully to ensure the good electrical performance of the multifunctional panels.